# Is it possible to fly a large aircraft inverted?

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• Is it possible to fly a large aircraft inverted? blended

I am curious if the inverted plane in the movie Flight 2012 has anything to do with reality / emergency practices. And if it does, can you please explain the concept/ aerodynamics behind of it , or why someone would ever do that even as last resort?

• FedEx 705 underwent extreme maneuvers, even inverted flight. The captain was trying to disorient a hijacker while the first officer fought him hand-to-hand.

Here's a dramatization of it. Not sure if it's the best one but there are others.

Most of your airfoils are designed to produce lift at 0 angle of attack (a perfectly symmetrical airfoil will not), which means that although it's more difficult than with a symmetrical airfoil, you can fly (inverted) at an angle that they will produce lift at negative angles as well. You will be inverted with the nose very high above the horizon, higher than it would be for level flight at a normal attitude.

Beyond that, the aircraft is really not built to do invert maneuvers. Legally they must be able to withstand -1G, but that doesn't leave much room to maneuver while inverted. In reality, most aircraft are designed beyond legal limits just for safety. On top of that, just because an aircraft is rated for a certain load limit does not mean that it will catastrophically fail if that limit is exceeded. It may bend and wrinkle beyond repair, but it should take a lot more than that to fall apart. The problem is that you have no guarantee.

• In the movie Flight (2012), Captain Whittaker (Denzel Washington) does not explain why he deliberately inverted his aircraft, but the obvious inference is: since the horizontal stabilizer has slipped off its jackscrew and become jammed into a descent angle beyond the authority of the elevators to correct, in inverted flight this would push the nose far above the horizon and result in either a climb or a stall.

In this attitude, Whittaker would have been pulling back on the yoke to prevent the stall. In the movie, this worked. The aircraft was still not under control, but was no longer diving and overspeeding. Suddenly rolling the aircraft upright in the last seconds before contact with terrain is the unrealistic part. A hot fighter jet might accomplish this but the roll rate of a passenger jet is too slow.

The movie's flight emergency is based mostly on the crash of Alaska Airlines flight 261 on January 31, 2000. In that incident, the pilots experienced a jammed horizontal stabilizer with uncontrollable dive, and inverted their MD-80 to arrest their descent. Unfortunately in real life neither flying officer was stuffed to the gills with booze and coke: the maneouver failed and the aircraft crashed with no survivors.

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• Spencer Suderman recently did a world record 81-turn inverted flat spin, and dropped over 21 thousand feet while doing so. The entire thing is documented on youtube. The spin starts at 3 minutes into the clip. Looking at the footage, in the beginning of the spin, and also (although to a lesser extent) at the end of the spin, the altimeter is unwinding very unevenly, being almost steady for a second and then quickly unwinding 3-500 feet before steadying (or actually increasing the first couple of turns) for another second. Why is that? It seems unreasonable to me that it would actually

• I am curious if the inverted plane in the movie Flight 2012 has anything to do with reality / emergency practices. And if it does, can you please explain the concept/ aerodynamics behind of it , or why someone would ever do that even as last resort?

• I'm simplifying here, but every introduction to flying shows us that the profile of a wing leads to lower pressure on the upper side of the wing, hence the wing and the plane attached to it will be pulled up. All right. How does that explain a plane flying inverted? If the explanation was right, the plane would pull itself towards earth.

• Is there generally a minimum altitude for ejecting in order for the sequence to function reliably (all the way to opening the chute, and slowing down to a survivable descent rate)? I've seen ejector seats test being done on the ground, don't know if there were actually test pilots in those seats though. I assume all bets are off if you're not wings level (obviously a low-level inverted ejection has a 0% chance of success).

• When I was learning for my license, one of the first diagrams I remember was about the wing profile. The air going around the wing and on the upper side it has to travel a longer way, thus generating lower pressure and bang, plane is flying. Same explanation already back at school. See my other question: if the theory was right, why can planes fly inverted? So here's the follow up: why is this wrong theory so popular and still part of books? Wouldn't it make sense to teach students how a wing really works? I mean just look at any RC plane meeting - you'll be amazed what weird designs

• KORD airport for instance charges domestic vs international arrivals differently. I could see that this may have something to do with imports/taxes/tariffs etc, but why are the landing fees measured in \\$ per 1,000lbs?

• I was watching some police programme on TV the other day, with an air chase that had the police helicopter crew on their toes; having to perform a lot of sudden maneuvers. How do police, or HEMS (medical), helicopters communicate with ATC? I presume they get priority, but do ATC clear other traffic out of the way? Is there a comms person/navigator on-board? Do they simply "see and avoid"?

• What does ATC do when there is an emergency? This could be a tower or an ARTCC being evacuated or otherwise unusable. How do they decide whether to close the airport/airspace? What do they do with the traffic, whether they do or don't close? On this related question, it turned out that Newark closed because of smoke in the tower. Another user posted an interesting anecdote about another tower being evacuated, so I thought it warranted a question.

• What can I do if my not-so-newly issued temporary pilot certificate is about to expire and I haven't gotten my permanent certificate yet? Is there any way that I can keep flying while waiting for it, and is there a way to check on the status of the permanent certificate?

• In aeroelasticity, there are three main phenomena that one should take care of: divergence, aileron reversal and flutter. Each of them has an associated speed at which the phenomenon might start to occur. During wind-tunnel tests it is possible to increase the flutter speed to have access to the divergence speed first by using some small masses smartly placed on the wing. This is due to the fact that usually flutter speed is smaller than divergence speed. Is it always the case for aircraft (without additional masses on the wing)? If not do you have any example? If yes do you have

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